<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <link rel="stylesheet" href="./css/index.css" />
  <title>记事本</title>
</head>

<body>
  <!-- 主体区域 -->
  <section id="app">
    <!-- 输入框 -->
    <header class="header">
      <h1>小黑记事本</h1>
      <input  v-model="todo" placeholder="请输入任务" class="new-todo" />
      <button class="add" @click="add">添加任务</button>
    </header>
    <!-- 列表区域 -->
    <section class="main">
      <ul class="todo-list">
        <li v-for="(item,index) in todoList" :key="item.id" class="todo">
          <div class="view">
            <span class="index">{{item.id}}.</span> <label>{{item.name}}</label>
            <button class="destroy" @click="deletes(item.id)"></button>
          </div>
        </li>
      </ul>
    </section>
    <!-- 统计和清空 -->
    <footer class="footer">
      <!-- 统计 -->
      <span class="todo-count">合 计:<strong> {{this.todoList.length}} </strong></span>
      <!-- 清空 -->
      <button class="clear-completed" @click="clear">
        清空任务
      </button>
    </footer>
  </section>

  <!-- 底部 -->
  <script src="./../vue.js"></script>
  <script>

    const app = new Vue({
      el: '#app',
      data: {
        todoList: [
          { id: 1, name: '吃火锅'},
          { id: 2, name: '敲代码'},
          { id: 3, name: '学vue'},
        ]
      },
      methods:{
        //删除 1.绑定 2.写方法
        deletes(id){
          this.todoList = this.todoList.filter(item =>item.id != id)
        },
        //增加
        add(){
        //1.设置输入内容不能为空
        if(this.todo.trim() == ''){
          alert('输入内容不能为空')
          return
        }
        //2.把输入的内容包装成一个对象
        const obj = {
          id:this.todoList.length+1,
          name:this.todo
        }
        //3.把输入的内容添加到数组
        this.todoList.push(obj)
         //4.写入后清空输入框
        this.todo = ''
        },
        clear(){
          this.todoList= []
        }
       
       
      }
    })

  </script>
</body>

</html>